Preheat your oven to 180°C (356°F) and remove the seeds from your fresh chilies. Spread them out on a baking sheet and roast in the oven for about 10 minutes until they become dehydrated and fragrant.

While the chilies are roasting, finely chop the garlic, red shallots, and optional galangal.

Roughly chop the tender white part of the lemongrass into 1-2 cm segments. Place the chopped lemongrass in a food processor and blitz it until finely chopped.

In a small pan, add cooking oil along with the annatto seeds. Heat over low for about 3-5 minutes, watching closely as the oil turns a lovely reddish hue from the seeds. Once infused, strain the oil to remove the seeds.

In a medium pan, combine a bit more cooking oil, along with star anise and Chinese cinnamon bark. Heat over low for about 2 minutes until fragrant, stirring occasionally.

Add the chopped garlic, shallots, and galangal to the sizzling oil. Cook over medium heat for about 1 minute, stirring frequently.

Stir in the prepared lemongrass, roasted chilies, chili flakes, fish sauce, salt, sugar, and chicken bouillon powder. Cook on medium heat for about 10 minutes, stirring regularly until it turns a rich golden color.

Once well combined and golden, add the annatto oil and stir to incorporate. Allow the sauce to cool to room temperature before transferring it to clean, airtight containers.